Holographic colored light pattern simulation

ABSTRACT

A method of generating a holographically reconstructed image of a model object so that the image will appear to have lamps of various predetermined colors at predetermined locations and having predetermined sectors of viewability in which color is generated from a laser light source having a coherent beam output comprising a plurality of wavelengths characteristic of different colors and wherein packs of fiber optics are utilized to carry selected color light for presentation at predetermined locations on the model object. The ends of the optic fibers of the model are received in the model at selected distances from a face thereof as desired to provide desired angles of view whereat the lights become apparent to the viewer of the multicolor holographic image dependent upon the use to which the resultant holographic image is directed. One such use is in the simulation of a Fresnel Lens Optical Landing System used aboard aircraft carriers.

United State Mohon et al.

HOLOGRAPHIC COLORED LIGHT PATTERN SIMULATION inventors: Windell N.Mohon, Winter Park;

Alfred H. Bodemann; Geroge Derderian, both of Maitland, all of Fla.

Appl. No: 242,959

[ Sept. 25, 1973 Primary ExaminerHerman Karl Saalbach Attorney-RichardS. Sciascia et al.

[ 5 7 ABSTRACT A method of generating a holographically reconstructedimage of a model object so that the image will appear to have lamps ofvarious predetermined colors at predetermined locations and havingpredetermined sectors of viewability in which color is generated from alaser light source having a coherent beam output comprising a pluralityof wavelengths characteristic of different colors and wherein packs offiber optics are utilized to carry selected color light for presentationat [52] US. Cl. 350/15, 35/12 N predetermined locations on the modelObject. The ends [51] Int. Cl. G02b 27/00, 00% 9/08 of the Optic fibersof the mode] are received in the [58] F'eld Search 35/12 12 Bi model atselected distances from a face thereof as de- 35O/3'5 sired to providedesired angles of view whereat the lights become apparent to the viewerof the multicolor [56] References cued holographic image dependent uponthe use to which UNITED STATES PATE TS the resultant holographic imageis directed. One such 3.533.104 10/1970 Habegger 250/35 us is n the m atn of a Fresnel L s Optical L d- 3,567,305 3/1971 Collier et al. 350/35ing System used aboard aircraft carriers. 3.580.656 5/l97l Carson 350/353,600,055 8/1971 Emerick 35/12 N 5 Claims 8 Drawmg Figures I2 56 LASER 6BEAM BEAM SPLITTER 5 SPLITTER :i7 5 J a HOLOGRAPHIC "PLATE 0 AIRCRAFT 6CARR'ER FIBER OPTIC BUNDLE 5O MIRROR PAIENIEBW 3.761.156

sum 1 0f 5 FIG. I

Pmman tre 3.761.156

SHEET 2 BF 3 l6 LASER B {RED 28 3 36 as 9 \1 U A GR DICHROIC MIRRORSFIG. 2

FIG. 3 FIG. 4

O O O O Q o o I 2 3 4 5 6 7 b 0 I0 I] O FIG. 6

IIOLOGRAPIIIC COLORED LIGHT PATTERN SIMULATION BACKGROUND OF THEINVENTION The invention relates to the fields of holographicallyreconstructed images and to simulation by such means for trainingpurposes.

In the past holograms have been used in simulation apparatus for varioustraining applications. Patterns of lights have been used in suchapplications as the simulation of Fresnel Lens Optical Landing Systems.In such latter simulations, lights of different colors have been used toindicate a base line and various angles of glide toward a carrier deck.The operation of such lights in coordination with the relationship ofthe aircraft and carrier deck have been acomplished by computerizedelectrical or electromechanical means including complicated gatingcircuits. Problems in relation to the prior art approaches relate toundesirable size, cost, maintenance, and performance of requiredequipment.

SUMMARY OF THE INVENTION The present invention is directed to the use ofoptic fibers as the object in a multicolor hologram and the use of acoherent laser light source having a plurality of wavelengthscharacteristic of different colors and positioning the object end of theoptic fibers in recessed passageways of a holder mounted on the carrierdeck such that a holographically reconstructed image of the carrier andthe light pattern formed in the holder may be generated. Such image willthen appear to have lamps of various predetermined colors and patternsat predetermined locations and will present predetermined sectors ofviewability corresponding to a Fresnel Lens Optical Landing System butwithout the need for computer assist on complicated electroniccircuitry. The holographically generated image itself simulates, via theviewability factor thereof, actual landing conditions. The same methodof forming a holographically generated image may also be employed inother applications.

DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic view of apparatusemployed in holographically generating an image in accordance with theinvention;

FIG. 2 illustrates a modification of a laser ray wavelength dividermeans portion of the apparatus shown in FIG. 1;

FIGS. 3 and 4 illustrate a method of recessing optic fibers to vary theviewing angle;

FIG. 5 is an elevational view of a holder for the object ends of theoptic fibers;

FIG. 6 is a sectional view taken on line 6-6 of FIG.

FIG. 7 is a diagrammatic view of the arrangement of apparatus forproducing the holographic image; and

FIG. 8 is a diagrammatic illustration of the formation of the endproduct holographic image.

DESCRIPTION OF THE PREFERRED EMBODIMENT The invention described hereinis an improved method of generating a holographically reconstructedimage of a model object so that the image will appear to have lamps ofvarious predetermined colors at predetermined locations and havingpredetermined sectors of viewability. The invention is useful in anyapplication in which the simulation of an object with light effectfactors as described above is desired in a training aid. The inventionwill be described by way of example in relation to one specificapplication wherein the method is employed in the simulation of aFresnel Lens Optical Landing System (FLOLS used aboard aircraftcarriers, in a holographic carrier landing trainer. The FLOLS iscomposed of a series of colored lights which produce a datum patternincluding one series of green lights for a datum line of reference, asecond series of yellow lights positioned perpendicular to the datumline to indicate various angles of glide relative to the datum line, anda red light below the series of yellow lights indicating a dangerouslylow approach angle.

Referring to FIG. 2, there is shown diagrammatically the basic elementsemployed in the method of the invention. As shown in FIG. 1, a laserlight source 12 is utilized to produce a beam 14 derived from the laserlight source 12 as shown in detail in FIG. 7. The laser is selected ofthe type having a coherent laser beam output comprising a plurality ofwavelengths characteristic of different colors. For example, the Kryptonlaser is well suited for the intended real time simulation because itproduces wavelengths of several colors, including green, yellow, andred, and because the power available in the three colors mentioned issufficient to produce the necessary exposure on the holographic plate 42during the recording procedure (see FIG. 7), as well as the necessarylumens for visibility upon reconstruction of the multicolor hologram.

The laser beam is then passed through a wavelength divider means whichis shown in FIG. I as the prism 15 and in FIG. 2 as the dichroic mirrors16, 18 and 20. The preferred form is the prism 15, as in FIG. 1, whichdivides the beam into three wave forms 22, 24 and 26 representative ofthe colors red, yellow, and green. The split beams 22, 24 and 26 aredirected respectively to packs of optic fibers 28, 30 and 32, the endsbeing held by a holder 34. The packs are held in an optic bundle 36 andthe other ends of the fiber packs are connected in an object holder 38in a manner to form a FLOLS pattern as will be described. The holder 38is mounted on a model 40 of an aircraft carrier which will be part ofthe holographically generated image.

FIG. 2 is provided to show the alternate method of using mirrors 16, I8and 20 and also to show how each fiber pack which contains one orseveral optic fibers, as required, is branched out at the object end inindividual optic fibers, as shown, to provide in this particularapplication one red optic fiber, four yellow optic fibers and six greenoptic fibers. In FIG. I, the fiber packs 28, 30 and 32 are branched outat the object end in the same manner and housed in associated passagesof the object holder 38.

Referring now to FIG. 5, there is shown an elevational view of the frontface of the object holder 38 and showing the Fresnel image pattern ofpassageway ends at which the individual optic fibers terminate. Thepattern includes the passageways l, 2, 3, 5, 6 and 7 in which opticfibers emitting a green light will be located to provide a horizontaldatum line of green lights. In vertical alignment are passageways ll, 4,l0, 9 and 8. A red light emitting fiber is located in passageway 11, and'in passageways 8, 9, 10 and 4 yellow light emitting optic fibers arelocated.

As shown in the cross sectional view of FIG. 6 in conjunction with theelevational view of FIG. 5, the passageways numbered I to 7 are drilledparallel to the base line a b of holder 38. The base line a b isparallel to the correct flight path for a plane landing on the carrier40. The passageways 9, 8 are drilled at increasing angles upward fromthe base line a b. The passageways 10 and 11 are drilled atincreasingangles downward from the base line a b. Each of the angles forpassageways 9 and 8 correspond to the angle above the flight path atwhich the light in that particular passageway will be seen by a pilotapproaching the carrier. For example. if the plane is approaching thecarrier at a very high angle, the pilot will see only the light at theposition, passageway 8, because of its upward angle and none of thelights in passageways 9, 4, l and II. The lights in passageways 10 and11 simulate a too low approach and will be seen, because of theirdeclining angle. when the pilot approach is below the desired angle ofapproach.

The lights to which reference is made above is the light passed on eachindividual optic fiber from the laser light source. Green fibers, i.e.,the fiber of fiber pack 32 receiving green light from the laser, arepositioned in the passages l, 2, 3, S, 6 and 7 and pushed through untilthey are nearly flush with face b c of holder 38. This allows the greenlights to be seen over a large angle, see angle A of FIG. 3, as requiredfor the datum line on the FLOLS. Yellow fibers, those from fiber pack30, are positioned in passageways 8, 9', l0 and 4 and pushed into thecompartments only part way to the face b c. This limits the angle overwhich these lights are visible to the pilot as shown by the smallerangle B in FIG. 4. The red fiber, from the single fiber pack 28, ispushed in part way in passageway 11 such that its angle of visibility isalso limited to angle B of FIG. 4. As one views the above describedpattern he will see the correct colored lights over the appropriateangles. The green light line is visible over approximately 40 degreesangle in the vertical and horizontal directions. The yellow and redlights are seen over about 2 degrees angle in the vertical andhorizontal.

The holder 38 and its enclosed optic fiber ends is now placed on thedeck of the aircraft carrier model 40. The model is then placed in aholographic set up. FIG. 7 illustrates diagrammatically one set up forforming the multicolor hologram. A laser beam 44 is passed into the setup and impinges on a beam splitter 46. A reflected beam 48 is thenredirected off a mirror 50, through a lens 52, to the holographic plate42, to act as the holographic reference beam. A beam 54 which passesthrough the beam splitter 46 impinges on a second beam splitter 56. Areflected beam 58 is then redirected off a mirror 60, through a lens 62,to the aircraft carrier model 40, to illuminate the model and act as apart of the holographic object beam. The derived laser beam 14 whichpasses through beam splitter 56 then impinges on the prism 15, to beseparated into the appropriate colors as described in relation toFIG. 1. The three individually colored beams then pass through the fiberoptic holder 38 on the deck of the aircraft carrier model 40. This setof fibers and the holder 38 now comprise a simulation of the FLOLS andact as a second component part of the holographic object beam. The

. 6 optical paths length of all object paths are ad usted to be equal tothe optical path of the reference beam to well within the coherencelength of the laser. The relative beam ratio of the reference beam tothe total object beam (aircraft carrier plus FLOLS) is then adjusted tobe an appropriate value. A holographic exposure is then made and theresulting hologram 64 is ready for use in a simulator. The hologram isreconstructed conventionally from the holographic plate 42 byilluminating it with a laser beam identical to or conjugate with theoriginal reference beam. The hologram is now ready for viewing. When apilot trainee views the holographically generated image he will see thecarrier and the FLOLS pattern. The green datum line will be apparent inproper respect to the carrier. The trainee will see the correct light onthe carrier deck to indicate his angle of approach. The holder 38 whichcan be made of wood, plastic, metal or other materials, will beoptically black to reduce reflections in the fiber passageways. Theholder 38 size will be determined by the scale of the carrier 40 towhich it is attached.

What is claimed is:

1. The method of generating a holographically reconstructed image of amodel object so that said image will appear to have lamps of variouspredetermined color at predetermined locations and said methodcomprising the following steps:

a. providing a model object,

b. providing a laser light source having a laser beam output comprisinga plurality of wavelengths characteristic of different colors,

0. providing a light source divider means positioned to divide a portionof said beam into characteristically colored .beams,

d. providing a plurality of light transmitting fibers, each having oneend positioned to receive light from a selected one of said coloredbeams and the other end located at said model in one of saidpredetermined locations so as to emit light of said selected color,

e. applying said laser beam to generate a hologram of said model andsaid light emitting fiber ends, and

f. illuminating said hologram with said laser beam to generate saidholographically reconstructed image including the light pattern of saidlight emitting fiber ends.

2. The method according to claim 1, including a. the step of groupingsaid light transmitting fibers in fiber optic bundles to provide formultiple lights of the same color at the object end in selectedlocations as desired.

3. The method according to claim 1, including a. the step of recessingsaid optic fiber ends in said model object a distance determiningdesired predetermined sectors of viewability.

4. The method according to claim 2, including a. forming said modelobject of the model of an aircraft carrier and a holder mounted thereonfor receiving the object ends of said fibers,

b. forming a first plurality of horizontal spaced passageways centraland above said base line in said holder, each succeeding passagewayabove the base line being inclined upwardly at successively increasingangle to receive fibers carrying yellow color light, and

d. forming a downwardly inclined passageway in said holder to receive afiber carrying red light, whereby said green, yellow and red lightcarrying fibers present a Fresnel Lens Optical Landing System patternand provide predetermined sectors of viewability to a trainee pilot in aholographic carrier viewing angle to adesired viewing angle suitable tolanding trainer. 5. The method according to claim 4, including a.varying the position of said optic fibers longitudimate hologram nallyin said passageways to vary the degree of 5 the approach landing patterndesired in the ulti- UNITED STATES PATIENT eraser CERTEFICATE @EFCRRECHN Patent No. 336L156 Dated Sept m r 25, 973

Inv n H windell N. Mohon, et a1.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

a In the heading Inventors "Alfred E. Bodemann" should read Alfred H.Rodemann Signed and sealed this 26th day of February 197M (SEAL) Attest:

EDWARD M.FLETCHER,J'R.' MARSHALL DANN Attesting fficer 1 Commissioner ofPatents FORM Po-wso (10-69) USCOMM-DC 60376-P69 Q ".5. GOVERNMENTPRINTING OFFICE: 19? O3$5-3S,

1. The method of generating a holographically reconstructed image of amodel object so that said image will appear to have lamps of variouspredetermined color at predetermined locations and said methodcomprising the following steps: a. providing a model object, b.providing a laser light source having a laser beam output comprising aplurality of wavelengths characteristic of different colors, c.providing a light source divider means positioned to divide a portion ofsaid beam into characteristically colored beams, d. providing aplurality of light transmitting fibers, each having one end positionedto receive light from a selected one of said colored beams and the otherend located at said model in one of said predetermined locations so asto emit light of said selected color, e. applying said laser beam togenerate a hologram of said model and said light emitting fiber ends,and f. illuminating said hologram with said laser beam to generate saidholographically reconstructed image including the light pattern of saidlight emitting fiber ends.
 2. The method according to claim 1, includinga. the step of grouping said light transmitting fibers in fiber opticbundles to provide for multiple lights of the same color at the objectend in selected locations as desired.
 3. The method according to claim1, including a. the step of recessing said optic fiber ends in saidmodel object a distance determining desired predetermined sectors ofviewability.
 4. The method according to claim 2, including a. formingsaid model object of the model of an aircraft carrier and a holdermounted thereon for receiving the object ends of said fibers, b. forminga first plurality of horizontal spaced passageways central and abovesaid base line in said holder, each succeeding passageway above the baseline being inclined upwardly at successively increasing angle to receivefibers carrying yellow color light, and d. forming a downwardly inclinedpassageway in said holder to receive a fiber carrying red light, wherebysaid green, yellow and red light carrying fibers present a Fresnel LensOptical Landing System pattern and provide predetermined sectors ofviewability to a trainee pilot in a holographic carrier landing trainer.5. The method according to claim 4, including a. varying the position ofsaid optic fibers longitudinally in said passageways to vary the degreeof viewing angle to a desired viewing angle suitable to the approachlanding pattern desired in the ultimate hologram.